Pumpkin Spice Tres Leches Cake with Salted Caramel Buttercream Frosting

Ingredients

Cake:
• 5 large eggs (separated)
• 1/2 cup granulated sugar
• 2 teaspoons vanilla extract
• 1 cup all-purpose flour
Milks:
• 7 ounces sweetened condensed milk
• 5 ounces evaporated milk
• 1/2 - 1 cup heavy cream
• 1 teaspoon pumpkin pie spice
• 1 cinnamon stick
• 1/8 cup pumpkin puree
• 2 teaspoons rum
Frosting:
• 3 large egg whites
• 3/4 cup granulated sugar
• 2 sticks unsalted butter, diced and softened
• 1/4-1/8 teaspoon salt, to personal taste
• 1/2 tablespoon vanilla extract
• 1 cup thick caramel sauce

Instructions

Make Cake:
1. Preheat oven to 350 degrees. Spray a square 9x9-inch pan or 9-inch round cake pan with a baking spray containing flour. Set aside.
2. Separate the egg yolks from the egg whites and place in separate bowls.
3. Beat the egg whites on medium speed to soft peaks, about 3-5 minutes. Slowly add the sugar and continue whipping until stiff peaks form, about 5 minutes. Set aside.
4. In a medium bowl beat egg yolks at medium-high speed until pale and fluffy, about 5 to 6 minutes. Stir in vanilla. Pour the yolks over the whites and gently fold in. Sift the flour over the egg mixture and gently fold again, just until incorporated. Be sure not to over mix.
5. Gently scrape and then spread the batter into prepared pan. Bake in preheated oven for 25 minutes or until a toothpick inserted in the center comes out clean. Transfer cake to a cooling rack and cool completely.
Make Milks:
6. Place sweetened condensed milk, evaporated milk, 1/2 cup heavy cream, pumpkin pie spice and cinnamon stick into a medium saucepan. Bring to a boil over medium high heat. Reduce heat and continue at a low boil for 5 minutes. Remove from heat. Cool completely. Remove cinnamon stick. Whisk in pumpkin puree and rum thoroughly. Mixture should be smooth and pourable. If needed, add remaining heavy cream.
7. Split the cake in half, if desired. Poke holes all over the cake using a wooden skewer. Brush the milk syrup over the cake a little at a time until all the milk mixture has been absorbed. Place cake in fridge overnight.
Frosting:
8. In a medium heatproof bowl, whisk together egg whites and sugar just to combine. Place bowl over a pot of barely simmering water. Bring mixture to 150 degrees Fahrenheit while whisking constantly.
9. Transfer mixture to the bowl of a stand mixer fitted with a whisk attachment. Beat egg white mixture at medium speed until mixture has cooled, doubled in volume and stiff peaks form.
10. With the mixer on low, add butter in one piece at a time, making sure each piece is fully incorporated before adding the next. Add salt and vanilla and beat again to combine. Add caramel sauce and beat one last time just to combine.
Assembly:
11. Remove milk soaked cake from refrigerator and allow to come to room temperature. Frost cake with salted caramel buttercream frosting. Serve drizzled with a bit of caramel and a light sprinkle of flaky sea salt, if desired.

Notes